A Wellington Water crew is working on a burst water main on Jervois Quay in the central city.
It said the leak has caused substantial surface flooding on the footpath and left-hand northbound lane of the road.
It said the only building which seems to be affected is 115 Jervois Quay, but it was checking the Michael Fowler Centre to ensure its water is still running.
It is anticipated water access will be interrupted for at least 6 hours.